acoperis_casa_metalica_XPS_alufolie_Osb, U=0,22

Open construction in editor

Dear all,

I find this on-line tool and I give it a try. But I find something that is not logic, and maybe someone can explain what is this happening.

Build 1
- trapezoidal metal dek (1)
- vapor retarder (2) sd=5m
- Extrude polystyren XPS 035 (3)
- OSB/3 (4)
- EPDM Foil (5)
This is the classical build of a flat metal roof construction.
For this build the calculation will give me in the summer time (outside 40°C, RH 60%) condens.

Build2
- trapezoidal metal dek (1)
- Extrude polystyren XPS 035 (3)
- vapor barrier (2) sd=1500m
- OSB/3 (4)
- EPDM Foil (5)
No Condens.


If I put the vapor barrier on insulation and without any vapor retarder on metal deck I do not have any condense (winter / summer)
I did not see any build like this in reality for the moment. So my question: I have done something wrong?